docs: def Shacham_1980(Re, eD):
      r'''Calculates Darcy friction factor using the method in Shacham (1980) [2]_
      as shown in [1]_.
  
      .. math::
          \frac{1}{\sqrt{f_f}} = -4\log\left[\frac{\epsilon}{3.7D} -
          \frac{5.02}{Re} \log\left(\frac{\epsilon}{3.7D}
          + \frac{14.5}{Re}\right)\right]
  
      Parameters
      ----------
      Re : float
          Reynolds number, [-]
      eD : float
          Relative roughness, [-]
  
      Returns
      -------
      fd : float
          Darcy friction factor [-]
  
      Notes
      -----
      Range is 4E3 <= Re <= 4E8
  
      Examples
      --------
      >>> Shacham_1980(1E5, 1E-4)
      0.01860641215097828
  
      References
      ----------
      .. [1] Winning, H. and T. Coole. "Explicit Friction Factor Accuracy and
         Computational Efficiency for Turbulent Flow in Pipes." Flow, Turbulence
         and Combustion 90, no. 1 (January 1, 2013): 1-27.
         doi:10.1007/s10494-012-9419-7
      .. [2] Shacham, M. "Comments on: 'An Explicit Equation for Friction
         Factor in Pipe.'" Industrial & Engineering Chemistry Fundamentals 19,
         no. 2 (May 1, 1980): 228-228. doi:10.1021/i160074a019.
      '''
      ff = (-4*log10(eD/3.7 - 5.02/Re*log10(eD/3.7 + 14.5/Re)))**-2
      return 4*ff